Not sure what they put in the Cornerstone, but mine is an an Air Dream Ultra.
If you only need the air bladder like I did it's a $185.00 all in with free shipping and a 3 year warranty.
I had a warranty claim also and they handled it right away.
Open up the mattress cover and look at the bottom and find the name and batch number.
Check your size on the web site and call and order it.
https://www.airdream.net/air-dream-u...gdshj3mu4nf0a0